NEW C-2 SYMMETRICAL AND SEMISYMMETRICAL SUBSTITUTED IMIDAZOLIUM RIBONUCLEOSIDE - IMIDAZOLIC NUCLEOSIDES ANALOGS

New C-2 symmetrical imidazolium ribonucleosides have been synthesized. The silyl Hilbert Johnson-Vorbrugen method was used. Subsequent coupl ing of trimethylsilylimidazole with the peracylated D-ribofuranose 1, followed by removal of the protecting groups, afforded 1,3-bis(beta-D- ribofuranosyl)imidazolium 7 and 1-(beta-D-ribofuranosyl)imidazole 8. I n a similar synthetic sequence, 4(5)-substituted bis-ribofuranosylimid azolium 14 was also prepared, For the selective preparation of the mon oglycosylated imidazole 15, the classical method starting from 2,3,5-t ri-O-benzoyl-D-ribofuranosyl bromide in acetonitrile and using Hg(CN)2 was employed. These new base modified nucleosides were devoid of acti vity against HIV and cytotoxicity. Copyright (C) 1996 Elsevier Science Ltd.